4.4.3.4 Carbon dioxide capture and storage

In the absence of explicit policies, CCS is unlikely to be deployed on a large scale by 2030 (IPCC, 2005). The total CO2 storage potential for each region (Hendriks et al. 2004; Table 4.17) appears to be sufficient for storage over the next few decades, although capacity assessments are still under debate (IPCC, 2005). The proximity of a CCS plant to a storage site affects the cost, but this level of analysis was not considered here. CCS does not appear in the baseline (IEA, 2004a). Penetration by 2030 is uncertain as it depends both on the carbon price and the rate of technological advances in costs and performance.

Coal CCS

ABARE (Fisher, 2006) suggested that worldwide by 2030, 1811 TWh/yr would be generated from coal with CCS (17 EJ); 7871 TWh (73 EJ) from coal without; 1492 TWh (14 EJ) from gas with; and 6315 TWh (59 EJ) from gas without. CCS would thus result in around 4.4 GtCO2 of GHG emissions avoided in 2030 giving a 17% reduction from the reference base case level (Figure 4.25). In contrast, the ETP mitigation assessments for CCS with coal plants ranged between only 0.3 and 1.0 GtCO2 in 2030 (IEA, 2006a), given that commercial-scale CCS demonstration will be needed before widespread deployment.

In this analysis, CCS is assumed to begin only after 2015 in OECD countries and after 2020 elsewhere, linked mainly with advanced steam coal plants installed with flue gas separation, although these IGCC plants and oxyfuel systems are only just entering the market (Dow Jones, 2006). Assuming a 50-year life of coal plants (IEA, 2006a) and that 30% of new coal plants built in OECD and 20% elsewhere will be equipped with CCS, then the replacement rate of old plants by new designs with CCS incorporated is 0.6% per year in OECD and 0.4% elsewhere. Then 9% of total new and existing coal-fired plants will have CCS by 2030 in the OECD region and 4% elsewhere. Assuming 90% of the CO2 can be captured and a reduced fuel-to-electricity conversion efficiency of 30% (leading to less power available for sale – IPCC, 2005), then the additional overall costs range between 20 and 30 US$/MWh depending on the ease of CO2 transport and storage specific to each plant (Table 4.17).

Table 4.17: Potential emissions reduction and cost ranges in 2030 from CCS used with coal-fired power plants.

Share of plants with CCS (%)

Coal-fired power generation with CCS (TWh/yr)

Annual emissions avoided (GtCO2-eq/yr)

Total potential storage volumea (GtCO2)

Cost ranges (US$/tCO2-eq)

v

Highest

OECD

9

388

0.28

71-1025

28

42

EIT

4

14

0.01

114-1250

22

33

Non-OECD

4

253

0.20

291-3600

26

39

World

6

655

0.49

476-5875

a Hendriks et al, 2004

Gas CCS

The assumed life of a CCGT plant is 40 years, and with 20% of new gas-fired plants utilizing CCS starting in 2015 in OECD countries and 2020 elsewhere, then the replacement rate of old plants by new designs integrating CCS is 0.5% per year. By 2030 7% of all OECD gas plants will have CCS and 5% elsewhere. Assuming 90% of the CO2 is captured, a reduction of gas-fired power plant conversion efficiency of 15% (IPCC, 2005), and an additional overall cost ranging between 20 and 30 US$/MWh generated, then the costs and potentials by 2030 (compared with the IEA (2004a) baseline of no CCS) are assessed (Table 4.18). The costs for both coal and gas CCS compare well with the IPCC (2005) range of 15–75 US$/tCO2 (Table 4.5).

Table 4.18: Potential emissions reduction and cost ranges in 2030 from CCS used with gas-fired power plants.